Ask A Scientist© Molecular Biology Archive

name        aleksandra
status      student
age         20s
>
Question -  why do drugs that affect bacterial
ribosomes not also affect host cell ribosomes

>Bacterial ribosomes are structurally different from
>eukaryotic (host cell) ribosomes. For instance,
>bacterial ribosomes have two ribosomal RNA molecules,
>whereas eukaryotes have three (5S rRNA is missing in
>bacteria). There are also sufficient RNA sequence
>differences that allow drugs to act specifically.
>
>Trudy Wassenaar

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>Because bacterial ribosomes are just a little bit different.  Ribosomes are
>made of two subunits:  the large subunit and the small subunit.  When
>translation is about to take place, the two subunits come together to form a
>functional ribosome.  The small subunit is called 30s because of the rate at
>which it sediments during centrifugation.  The large subunit is different in
>bacteria and eukaryotes (50s vs. 60s) so eukaryotic ribosomes are larger than
>bacterial.  Different antibiotics interfere with ribosomal synthesis in
>different ways.  One prevents the attachment of the small subunit to the
>large subunit.  This is specific to bacterial ribosomes.  So the antibiotic
>affects the bacteria's protein synthesis but not the host cell's protein
>synthesis.
>
>van hoeck
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>Bacterial ribosomes are slightly different in their structure from our
>ribosomes. Drugs are so specific that the differences in the two kinds of
>ribosomes are sufficient to prevent ours from being affected while the
>bacterial ribosomes are shut down.

Mayo
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